Field of the Invention
The present invention generally relates to common-mode clamping circuits, and more particularly to circuits and methods that utilize cascode circuits in common-mode clamping.
Description of Related Art
Differential signaling is widely used in many applications. A differential signal comprises a first end and a second end, wherein a value of the differential signal is equal to a difference between a value of the first end and a value of the second end. A mean value between the first end and the second end is referred to as a value of a common-mode signal associated with the differential signal. In a differential circuit, the differential signal is what is of interest. On the other hand, the common-mode signal carries no useful information but uses a part of a dynamic range of the differential circuit. Therefore, the common-mode signal is typically undesirable and generally should be suppressed. A common-mode clamp is a circuit that is configured to suppress (or clamp) a common-mode signal of a differential circuit. A common-mode clamp usually needs to sense a value of the common-mode signal, and then perform the suppression based on the sensed value.
It is desired to provide improved clamping circuits for common mode signaling systems.